Microsoft October 2026 update fixes over 1,400 flaws; one exploited
The October 13, 2026 release is Microsoft's largest monthly security update, and it includes a Windows Shell bypass already used in attacks.
Microsoft released its October 2026 monthly security update on October 13, 2026, fixing more than 1,400 vulnerabilities — the most ever in a single Microsoft monthly release, according to ascii.jp.
The update addresses critical-severity issues across Windows, Office, Exchange Server, SharePoint, .NET and Visual Studio.
Among the fixed flaws is a vulnerability in the Windows Shell that bypasses a security feature, tracked as CVE-2026-96951. That issue had already been exploited in attacks before the update was published.
Microsoft is urging users to apply the update promptly and to check Windows Update.
What users should do
The company's guidance is to install the release as soon as possible through Windows Update rather than delay patching.
Quick answers
When was Microsoft's October 2026 security update released?
Microsoft released the update on October 13, 2026.
How many vulnerabilities does the October 2026 update fix?
It fixes more than 1,400 vulnerabilities, the most ever in a single Microsoft monthly release.
Was any vulnerability exploited before the update?
Yes. A Windows Shell vulnerability tracked as CVE-2026-96951 bypasses a security feature and had already been exploited in attacks before the update was published.